CVE-2005-0504 in Linux
Summary
by MITRE
Buffer overflow in the MoxaDriverIoctl function for the moxa serial driver (moxa.c) in Linux 2.2.x, 2.4.x, and 2.6.x before 2.6.22 allows local users to execute arbitrary code via a certain modified length value.
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Analysis
by VulDB Data Team • 06/11/2019
The vulnerability identified as CVE-2005-0504 represents a critical buffer overflow flaw within the Linux kernel's moxa serial driver implementation. This issue affects multiple kernel versions including 2.2.x, 2.4.x, and 2.6.x prior to 2.6.22, making it a widespread concern across the Linux kernel landscape during that era. The vulnerability specifically resides in the MoxaDriverIoctl function within the moxa.c driver file, which handles ioctl operations for Moxa serial devices. The flaw manifests when the driver processes certain ioctl commands with modified length values that exceed the allocated buffer space, creating conditions ripe for exploitation by malicious actors.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The buffer overflow occurs during the processing of ioctl commands that manipulate device parameters, particularly when the length parameter is manipulated to exceed the expected buffer boundaries. This type of vulnerability is particularly dangerous because it operates within kernel space, meaning successful exploitation can lead to complete system compromise. The vulnerability leverages the fact that the kernel driver does not properly validate the length parameter before copying data into fixed-size buffers, creating a classic buffer overrun scenario.
From an operational perspective, this vulnerability presents a significant risk to systems running affected Linux kernel versions, particularly those utilizing Moxa serial devices in production environments. Local users with access to the system can exploit this flaw to execute arbitrary code with kernel-level privileges, effectively bypassing all user-mode security controls and access restrictions. The attack vector requires only local access to the system, making it particularly concerning for environments where privilege separation is crucial. Once exploited, attackers can gain root-level access to the system, potentially leading to complete system compromise, data exfiltration, or establishment of persistent backdoors. The widespread adoption of affected kernel versions means that numerous systems across different industries could be vulnerable to this attack.
The mitigation strategies for this vulnerability primarily focus on kernel version updates, with the most effective solution being the upgrade to Linux kernel 2.6.22 or later, which contains the necessary patches to address the buffer overflow condition. System administrators should prioritize applying the official kernel patches provided by the Linux kernel community and vendors. Additionally, implementing proper access controls and privilege separation can help reduce the attack surface, although these measures do not eliminate the vulnerability itself. Network segmentation and monitoring for suspicious ioctl activity may provide additional defensive layers, though they are not comprehensive solutions. The vulnerability also highlights the importance of proper input validation and bounds checking in kernel drivers, which aligns with ATT&CK technique T1068 for privilege escalation and T1543 for kernel-level persistence mechanisms. Organizations should conduct thorough vulnerability assessments to identify systems running affected kernel versions and implement remediation plans accordingly, given the potential for remote exploitation and the critical nature of the underlying security flaw.